1. Field of the Invention
This invention relates generally to methods and devices for invasive medical treatment. More particularly, this invention relates to improvements in catheters.
2. Description of the Related Art
Cardiac arrhythmias, such as atrial fibrillation, occur when regions of cardiac tissue abnormally conduct electric signals to adjacent tissue, thereby disrupting the normal cardiac cycle and causing asynchronous rhythm.
Procedures for treating arrhythmia include surgically disrupting the origin of the signals causing the arrhythmia, as well as disrupting the conducting pathway for such signals. By selectively ablating cardiac tissue by application of energy via a catheter, it is sometimes possible to cease or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions.
One such catheter is proposed in PCT patent document WO 2012/174375. The catheter has a balloon that may be expanded at some portions along its length through inflation. The catheter may have one or more differently compliant sections along its length, or may have a generally noncompliant body with one or more separate compliant portions overlying it. The compliant portions may be separately inflated to create, in one section of the catheter an expanded disk-like configuration with a circular, somewhat planar surface that is oriented orthogonally to the direction of the guide wire and facing in a distal direction. The catheter bears one or more RF electrodes that are capable of conducting RF energy and may be positioned on the surface of the balloon such that they take a circular configuration on the planar surface.